The overall objectives of the proposed research are: (1) purify and identify the enterotoxin produced by the phage group II strains of staphylococci; (2) determine the physicochemical properties of the enterotoxin; (3) prepare specific antibodies to it; (4) compare the structure around the cystine loop to that of the other enterotoxins; (5) compare the cross-reactions of the enterotoxin produced by the staphylococci involved in the toxic shock syndrome to the enterotoxin produced by the strains involved in the scalded skin disease; and (6) supply other investigators with the necessary reagents to carry on their research in this field. Identification of the enterotoxin produced by phage group II staphylococcus strains will be accomplished by relating the toxin fractions (as determined by monkey feeding tests) obtained during purification to antibodies prepared to the partially purified toxin. The enterotoxin will be purified by chromatography on carboxymethyl cellulose, gel filtration using the Sephadexes and isoelectric focusing. The isoelectric point, molecular weight and amino acid composition of the purified enterotoxin will be determined by conventional methods. The tryptic peptides composing the cystine loop area will be separated by chromatography and sequenced by the Edman degradation method. Specific antibodies to the new enterotoxins will be prepared by methods developed in our laboratories using New Zealand white rabbits. The unidentified enterotoxin produced by the staphylococci implicated in the toxic shock syndrome will be compared to the unidentified enterotoxin produced by the staphylococci implicated in the scalded skin disease by comparing the cross-reactions with the antibodies against the latter enterotoxin. We plan to continue supplying other investigators with enterotoxin reagents because many worthwhile projects would not have been possible and will not in the future without our help.